Hydraulic control mechanism



June 4, 1940. R. c. LAMoND 2,203,097

HYDRAULIC CONTROL MECHANISM Filed April l5, 1937 2 Sheets-Sheet 1 HYDRAULIC CONTROL MECHANISM Filed April l5, 1937 2 Sheets-Sheet 2 Patented June 4, 1940 UNITED STATES PATENT -ol=l=lclaz HYDRAULIC CONTROL MECHANISM Application April 15, 1931, serial No. 131,051

6 Claims.

This invention relates to control mechanisms for hydraulic transmissions, especially those employed in steering devices for ships. In steering mechanisms of this character a reciprocating motor is employed to move the rudder to various positions of adjustment. The motor is driven by a reversible discharge pump which in turn, in most instances, is driven by an electric motor. Suitable controls are also provided to control the stroke and direction of discharge of the pump. During the operation of such devices, in the event the driving motor for the pump should become disabled, while the pump is on stroke, an hydraulic lock occurs in the system which retains the pump in that position. Upon reconditioning of the driving apparatus it is seen that in order to continue the operation of the device it would be necessary to start the operation thereof under a heavy load.

The present invention has for its primary object the provision of a safety means, preferably in the form of fluid motors connected to the pressure side of the system which function in the event the driving mechanism should become disabled for any reason, to return the stroke controls of the pump to neutral position. The driving mechanism for the pump may then be started up under practically no. load, and damage to the windings or the apparatus in general is prevented.

Other and further Objects will become apparent as the description of the invention progresses.

Of the drawings: e

Fig. 1 is a diagrammatic view partly in section, showing the invetion appliedto a steering mechanism for ships.

Fig. 2 is an enlarged plan view partly in section, showing the pump end of the transmission and the control mechanism associated therewith.

Fig. 3 is a sectional view showing the differential mechanism for adjusting the control valve of the stroke adjusting motor, and f Fig. 4 is a detail view partly in section, taken substantially ralong line 4-4 of Fig. 1.

Referring to the drawings, the numeral I designates generally a fluid motor driven in the present instance by a variable stroke reversible discharge pump 2, which in turn'may be driven by an electric motor 3, or by any other suitable driving mechanism. Pump 2 and motor 3 are mounted upon a makeup tank 4 from which fluid may be drawn into the system through connections hereinafter described. Pump 2 is of the general type shown and described in United States Patent No. 1,077,979 to which reference may be had for a complete description thereof.

Fluid motor I comprises a pair of spaced, axially aligned cylinders 5 and 6, having a ram I operating therein. Cylinders 5 and 6 are rigidly connected by a pair of tie rods 8 and 9. The outer ends of cylinders 5 and 6 are respectively connected to pump 2 by pipes I0 and il. Pump 2, as is well known in the art, is of such a construction that when the sliding blocks I2 thereof v are adjusted in one direction from a neutral position, pressure is delivered to pipe I I and suction to pipe I0, causing the ram 1 to move to the left and when the sliding blocks I2 are actuated in the reverse direction from a neutral position, pressure is delivered to pipe I and suction to pipe II, causing the ram I to move to the right. Extending vertically from ram `I intermediate the ends thereof is a projection I3, which operates in a slot I4, provided near the free end of an arm I secured to a rudder post I6. A rudder I'I, shown in dotted lines in Fig. 1, is secured to the lower end of post I6. It therefore is seen that upon actuation of ram 1 in the manner just described, rudder I1 is adjusted accordingly.

The stroke adjusting elements I2 of pump 2 are adjusted by means of a servo moto-r I8 which may be of the type shown and described in United States Patent No. 1,986,640. As shown more particularly in Fig. 2, servo motor I8 comprises a cylindrical casing I9 having a piston 20 operating therein. Fluid is supplied to servo motor IB by a small pump 2l, mounted in the present instance on motor 3 and driven by the armature shaft 22 thereof. Fluid is drawn into pump 2| from makeup tank I4 through a pipe 23, and is discharged therefrom through pipe 24. A branch pipe 25 connects pipe 24 with the inlet port 26 provided in the casing I9 of servo motor I8. Fluid at the low pressure end of servo motor I8 discharges to makeup tank through a port 21 also provided in casing I9 and pipe 28. The operation of piston 20 is controlled by a valve 29, the stem of which extends through the outer end of casing I9 and has pivotally connected to the free end thereof one end of a lever 3|. Piston 20 has secured thereto a rod 32 which extends through a suitable bearing provided in the inner wall 33 of casing I9, the outer end of which being secured to a crosshead 34. The opposite ends of crosshead 34 have secured thereto the outer ends of a pair of rods 35 which extend through suitable bearings provided in the end wall 36 of thecasing 3 1 of pump 2, while the inner ends of theserods are secured to the sliding blocks I2 of said pump. It therefore is seen that upon actuation of piston 28 of servo motor I8 the sliding blocks I2 are actuated accordingly to vary the stroke and direction of discharge of pump 2.

As shown in Fig. 1, lever 3| is mounted intermediate the ends thereof on a pair of coil springs 38 provided in a casing 39 and has pivotally connected to the left end thereof a rod 48. Rod 48 is secured to a cam follower 4| which in the present instance is actuated by a pair of cams 42 and 43. Cams 42 and 43 are adjusted by differential gearing indicated generally by the numeral 44. Cams 42 and 43 are secured to the vertical extension 45 of an operating element 46. The lower end of operating element 46 has secured thereto a bearing stud 41 upon which a bevel gear 48 is rotatably mounted. Operating element 46 is also provided with a pair of laterally extending bearing element-s 49 and 58 which extend respectively into the inner central bores 5| and 52 provided in a pair of axially aligned bevel gears 53 and 54 which mesh with bevel gear 48. Bevel gear 53 has integral therewith a hub portion 55 which extends through a suitable bearing 56 provided in the inner vertical wall 51 of the casing 58 for differential gear 44. The outer end of hub 55 has secured thereto a worm wheel 59 which meshes with a worm gear 68 secured to a shaft 6 I. One end of shaft 6| has secured thereto a spur gear 62 which meshes with a pinion 63 secured to a shaft 64 having a clutch element.

65 provided thereon. A second shaft 56 mounted in any suitable manner in axial alignment with shaft 64 is provided with a complementary clutch element 61, and has a hand wheel 68 secured to the outer end thereof. The other end of shaft 6| is secured in any suitable manner to the armature shaft 69 of a synchronous receiver 18, which in vturn is connected by suitable conductors 1| to a synchronous transmitter 12. Synchronous transmitter 12 may be located at some remote point on board ship, such as on the bridge thereof, and is connected by gearing 13 to a steering wheel 14. It therefore is seen that worm gear 68 may be actuated either by hand wheel 68 or by the synchronous transmitter 18, as desired.

Bevel gear 54 also has provided thereon an extended hub portion 15 which extends through a suitable bearing 16 provided in a second interior wall 11 of casing 58. 'I'he free end of hub 15 has secured thereto a worm wheel 18, which meshes with a worm gear 19 mounted on a followup shaft 88. Shaft 88, as shown more particularly in Figs. 1 and 4, is secured to a second shaft 8| by a universal coupling 82. Shaft 8| is rotatably mounted in a bracket 83 and has secured intermediate the ends thereof a bevel gear 84, which meshes with a second bevel gear 85 secured to the lower end of a shaft 86 mounted in a second bearing 81. The upper end of shaft 86 has secured thereto a gear 81 which meshes with a rack 88 integrally secured to ram 1 in any suitable manner, such as by a connecting element 89.

The various mechanisms hereinbefore described are of the general type shown and described in the pending application of Albert R. Kuzelewski, Serial No. 714,968, filed March 10, 1934, issued March 22, 1938 as Patent No. 2,111,594, to which reference may be had for a more detailed description thereof. However, from the foregoing description it is seen that upon movement of hand wheel 68 or 14, rotary movement is imparted to worm wheel 59, and bevel gear 53 which in turn actuates bevel gear 48. However, at this time inasmuch as bevel gear 54 is held stationary erating element 46, and consequently cams 42 and 43. By operation of cams 42 and 43 in this manner movement is imparted to cam follower 4I, which in turn swings lever 3| in one direction about its flexible pivot. This movement of lever 3| is imparted to valve 29 of servo motor I8, which properly conditions the servo motor for operation. When this occurs fluid from pump 2| will flow to the proper end of cylinder I9, depending upon the direction of movement of hand Wheel 68 o1' 14, causing piston 28 to actuate the sliding blocks |2 accordingly, thereby placing pump 2 on stroke. Let us assume that pump 2 has been so adjusted as to deliver pressure to pipe and suction to pipe I8. Under these conditions ram 1 will move to the left, carrying rack member 88 with it. This motion is imparted to worm gear 19 through gears 81, 85, 84, and shafts 8| and 88. By this action worm wheel 18 will actuate bevel gear 54 to return bevel gear 48 and actuating element 46 to normal position. 'I'his movement is again imparted to valve 29 through lever 3|,causing piston 28 to return the stroke controls of pump 2 to neutral position. Ram 1, and consequently the rudder |1 actuated thereby, will thus remain in adjusted position until hand wheels 68 or 14 are again operated.

Referring to Fig. 1, mechanism has also been provided to adjust valve 29 toward neutral position to thereby condition servo motor |8 to effect adjustment of sliding block |2 of pump 2 to reduce the stroke thereof in the event the pressure in the system exceeds a predetermined value. 'I'his mechanism consists of a pair of fluid motors 98 and 9|-which are connected to a. shuttle valve 92 by pipes v93 and 94 respectively. One end of shuttle valve 92`is connected to pipe I8 by a pipe 94, while the other end thereof is connected to pipe by a second pipe 95. Motor 98 consists of a cylinder 96 having a piston 91 operating therein. Piston 91 has a rod 98 secured thereto, which extends through the inner end of cylinder 96 and is secured to a crosshead 99 at the free end thereof. Crosshead 99 has secured to the opposite ends thereof a pair of. rods |8I, which extend through guide bearings provided in the flange |88 of cylinder 96. 'Ihe other ends of rods |8| extend through apertures provided in a rigid cross member |82. A pair of springs |83 encircle rods |8I and extend between cross member |82 and flange |88.

Motor 9| is of similar construction and also consists of a cylinder |84 having a piston |85 operating therein. The free end of piston rod |86 is secured to a crosshead |81 having secured to the opposite ends thereof a pair of rods |88. Rods |88 extend through guiding apertures provided in the flange |89 of cylinder 84, and also through guiding apertures provided in a rigid cross member |,|8. A pair of springs encircle rods |88 and extend between flange |89 and rigid member H8. A lever 2 pivoted intermediate its ends has provided at one end thereof a yoke ||3 adapted to engagea stud ||4 projecting from valve stem 38. The other end I5 of lever ||2 extends between and is adapted to be engaged by.

III

charging from pipe 94 to pipe 95. When this pressure exceeds the pressureof springs |03 and III associated with motors 90 and 9| respectively, pistons 91 and |05 will move inwardly to actuate lever H2 toward a central position. Lever |I2 in turn through its connection with valve stem 30 will then adjust valve 29 toward neutral position. When this occurs piston 20 will also be actuated toward a neutral position to effect adjustment of the sliding blocks I2 of pump 2 toward neutral position and thereby reduce the stroke of the pump. The same is true in the event the pressure in pipe II should exceed a predetermined safe value. When this occurs the ball H6 of shuttle valve 92 will be adjusted to the position shown in Fig. 1, thereby establishing communicationI between pipe II and motors 90 and 9|, which in turn actuate lever H2 toward a central position. Piston 20 of servo motor I8 now effects adjustment of sliding blocks I2 of pump 2 toward neutral position, to again reduce the stroke of the pump and thus relieve the pressure in the system.

Referring' to Figs. l and 2, it will be observed that pump 2 has secured to the end wall H1 thereof a bracket H8. Bracket H8 has mounted therein a pair of spaced, axially aligned fluid motors H9 and |20. Motor H9 comprises acylinder I2I 'having a piston |22 operating therein. A rod |23 secured to piston |22 extends through a suitable bearing provided in the end wall |24 of cylinder I2I. Cylinder I2I is provided with ports |25 and |26 at the opposite ends thereof. Motor I 20 also comprises a cylinder |21 in which operates a piston |28. A rod |29 extends through a suitable bearing provided in the end wall |30 of cylinder |21. Cylinder |21 also has provided therein a pair of ports I3| and |32. Extending between the ends of piston rods |23 and |29 is a crosshead |33, to the opposite ends of which are secured a pair of rods |34 and |35. These rods extend through suitable bearings provided in the end Wall I1 of pump 2 and are secured at their inner ends to sliding blocks I2.

It therefore is seen that when pistons |22 and |28 are actuated toward each other, crosshead |33 and consequently sliding blocks I2 will be actuated to neutral position to place the pump on neutral stroke. Port |26 of motor H9 is connected to a pipe |36 by means of a pipe |31. Port I3| of motor |20 is connected to pipe |31 by a branch pipe |28, while pipe |36 is connected to pipe 24, and therefore receives fluid from pump 2|. Pistons |22 and |28, it therefore will be observed, are normally actuated away from each other and are held in that position by the pressure of pump 2|. Ports |25 and |32 of motors H9 and |20 respectively, are connected by means of a pipe |39. Pipe |39 is connected to a port |40 of a control valve |4| by a pipe |40'. Control valve I4I comprises a substantially T-shaped casing |42 having la piston |43 operating therein. The outer wall- |44 of casing |42 has an inlet port |45 provided therein, to which the end of pipe |36 is connected. Piston |43 therefore is constantly subjected to the pressure delivered by pump 2| Piston |43 has integral therewith` aureduced portion |46 having provided intermediate the ends thereof a pair of transverse passages |41 and |48 connected by a third passage |49. The lower end of the reduced portion of the casing |50 has provided therein a port |5I which communicates with the chamber |52 of a. shuttle valve |53. The opposite ends of shuttle valve- |53 have provided therein ports |54 and I 55, the former of which is connected by a pipe |56 to pipe II, while the latter is connected to pipe I by a second pipe |51. Valve |53 comprises a ball valve |58 adapted to be actuated by pressure from one extreme end of chamber |52 to the other. When valve I4I is in the position shown in Figs. l and 2 passage |41 registers with an exhaust port |41' provided in the casing |42 thereof which in turn is connected to tank 4 by a pipe lI 41". Thus, when the valve is in normal position uid from the head ends of motors H9 and |20 drains to exhaust through pipes |39, |40', passages |48, |49 and |41, and pipe |41". Any uid leakage past piston |43 also flows to exhaust through port |41' and pipe 411i From the foregoing description it is seen that for normal operations of the apparatus as a whole, the piston rod ends of pistons |22 and |28 are constantly subjected to the pressure delivered by pump 2|. Pistons |22 and |28 are thus actuated away from each other, and retained in that position by this pressure. It is also seen that the outer end of piston |43 is alsogconstantly subjected to the pressure delivered by pump 2|, and therefore is retained in the position shown in Figs. 1 and 2. Now let us assume, for example, that pump 2 has been so adjusted as to deliver pressure to pipe I0 and suction to pipe I I. Fluid pressure from pump 2 now flows to the left hand end of cylinder causing ram 1, and consequently rudder' I1, to move to the right. Ball |58 of shuttle valve |53 will move to the right hand end of chamber |52, thereby preventing the passage of fluid from pipe |51 to pipe |56, and consequently the inner endof piston |43 will be subjected to the pressure in pipe I0. When the parts havebeen so adjusted, let us assume that the electric power is shut off, or that driving motor 3 should for any other reason become disabled and thereby come to rest. Under these conditions, due to the`pressure in pipe I0 pump 2 will be driven as a motor and will rotate motor 3, as well as pump 2|, in the opposite direction. Pump 2| then draws uid from valve I4I, the piston rod ends of motors H9 and |20, as well as from servo motor I8. This obviously reduces the pressure operating on these elements. Also, when auxiliary pump 2| comes to rest, a certain leakage occurs in the system, and consequently the pressure at the outer end of piston I43as well as that at connecting rod ends of motors H9- and |20, will be further reduced. If the ship is in motion, or in the event a wave should strikerudder I1, it will tend to move, depending upon the direction of application of the force. This force is transmitted to ram 1, which also tends to move in the direction of the application of the force, thereby tending to compress the fluid in pipes I0 or II. supposing the force is so applied that ram 1 tends to move to the left, thereby imposing pressure in pipe I0, the uid pressure thus created will be communicated to the inner end of piston |43. vThis pressure communicated to pump 2 also tends to operate the same as a motor to cause pump 2| to withdraw iluid from the outer end of piston |43 and the piston rod ends of motors H9 and |20, as well as from servo motor I8, and to discharge the 'same to makeup tank 4 through pipe 23.-, Inasmuch as the outer end of piston |43 is now subjected to substantially no pressure, piston |43 will move outwardly to establish communication between pipe I0 and the head ends of motors H9 and |20. As pointed out before, the connecting rod ends are subjected to substantially no pressure, and conse- `quently the pressure communicated to the headends of these motors will actuate the pistons |22 and 28 toward each other to thereby center crosshead |33, and consequently sliding blocks |2, thereby adjusting the pump to neutral position. Upon starting up of electric motor 3 it will be Seen that inasmuch as pump 2 is on neutral stroke the motor 3 will be subjected to substantially no load. The same procedure follows in the event the application of the force on the rudder Il should be in the opposite direction. Pressure will then be built up in pipe causing ball |58 of shuttle valve |53 to move to the extreme left hand position, thereby preventing the passage'of fluid from pipe |56 to pipe |57. The inner end of piston |43 will consequently be subjected to this pressure. Inasmuch as the upper end of piston |43 is subjected to substantially no pressure, the said piston will move outwardly to establish communication between the head ends of motors ||9 'and |20, and pipe The pistons |22 and |28 of motors H9 and |20 respectively will now move toward each other to actuate the sliding blocks I2 of pump 2 to a central position, and thereby place the said pump on neutral stroke.

The pressure applied to the upper end of piston |43, the piston rod ends of motors ||9 and |20, as well as that appliedto servo motor I by pump 2|, may be predetermined by means of a relief valve |60, mounted in pipe 24. Relief valve |60 comprises a casing |6| having a valve element |62 mounted therein. The stem |63 of valve element |62 extends through the central bore of a plug |64which makes threaded engagement with the right hand end (Fig. 2) of casing IBI. A coil spring |65 encircles valve stem |63 and extends between the valve head and the inner end of plug |64. Thus, by adjusting plug |64, the pressure of spring |65 may be varied. The casing |6| of valve |60 is also connected to makeup tank 4, by means of a pipe |66. During normal operation of the apparatus, when pistons |22 and |28 of motors H9 and |20, and piston |43 of control valve 4| have been actuated to their normal positions of adjustment, continued operation of pump 2| causes the pressure of the fluid to build up, and when this pressure exceeds the pressure of spring |65 of relief valve |60, valve element |62 will be actuated away from its seat to permit the fluid from pump 2| to bypass to makeup tank 4. n

Fluid is drawn into the system for makeup purposes from tank 4 through a valve |10"and pipes and'l12, the latter of which being connected to pipes I0 and While the embodiment herein described is admirably adapted to fulfill the objects primarily stated, it is to be understood that the invention is not to be limitedthereto, since it may be ernbodied in other forms', all coming within the scope of the claims which follow:

What is claimed is: A

1. In a fluid system, the combination with a reversible discharge pump, of power means for operating said pump, a reciprocatory fluid motor, a rudder actuated by said uid motor, stroke adjusting means 'for varying the stroke and direction of discharge of--said pump, a pair of fluid motors adapted to actuate said stroke controls to neutral position, a valve for controlling the operation of said pair of uid motors, means connecting one end of`said valve to the pressure in Valve by said auxiliary pump, said valve is actusaid system, an auxiliary pump actuated by said power means, and means connecting the other end of said valve to said auxiliary pump, whereby when the pressure in the system imposed upon said valve exceeds that imposed upon said Valve 5 by said auxiliary pump, said valve is actuated to establish communication between one end of said pair of fluid motors and said system pressure, causing said stroke adjusting means to be actuated to neutral position.

2. In a lluid system, the combination with a. reversible discharge pump, of power means for operating said pump, a reciprocatory uid motor, a rudder actuated by said fluid motor, stroke adjusting means for varying the stroke and direction of discharge of said pump, a pair of fluid motors adapted to actuate said stroke controls to neutral position, a valve for controlling the operation of said pair of fluid motors, means connecting one end of said valve to the pressure in said system, an auxiliary pump, means connecting the other end of said valve to said auxiliary pump, whereby when the pressure in the system imposed upon said valve exceeds that imposed upon said ated to establish communication between one end of said pair of fluid motors and said system pressure, causing said stroke adjusting means to be actuated to neutral position, and means connecting the other ends of said pair of fluid motors to said auxiliary pump, whereby the latter are normallyretained in ineifective position.

3. In a fluid system, the combination with a reversible discharge pump, of power means for operating said pump, a reciprocatory fluid motor, a rudder actuated by said fluid motor, stroke adjusting means for varying the stroke and direction of discharge of said pump, a pair of fluid motors adapted to actuate said stroke controls to neutral position, a valve for controlling the operation of said pair of fluid motors, means connecting one end of said valve to the pressure in said system, an auxiliary pump, means connecting the other end of said valve to said auxiliary pump, whereby when the pressure in the system 45 imposed upon said valve exceeds that imposed upon said valve by said auxiliary pump, said valve is actuated to establish communication between one end of said pair ofy fluid motors and said system pressure, causing vsaid stroke adjusting means to be actuated to neutral position, means. connecting the other ends of said pair of fluid motors to said auxiliary pump, whereby the latter are normally retained in ineiective position, and adjustable means for varying the pressure delivered by said auxiliary pump.

f1. In a iluid system, the combination with a reversible 'discharge-4 pump, of power means for operating said pump, a iluid motor operated by the discharge of said pump, a rudder operated .by said fluid motor, stroke adjusting means for varying the stroke and direction of discharge of said pump, an auxiliary source of fluid pressure, means operated by said auxiliary source of fluid pressure for actuating said stroke adjusting means to different positions of adjustment, a pair of uid motors adapted to actuate said stroke adjusting means to neutral position, a valve for controlling the operation'of said pair of fluid motors, means connecting one end of said valve to the pressure in said system, means connecting the other end of said valve to said auxiliary source oi' pressure whereby when the pressure in the system imposed upon said valve exceeds that imposed. upon said valve 'by said auxiliary source of 75 pressure, said valve is actuated to establish com- 5. In a fluid systemfthe combination with a reversible vdischarge pump, of power means for operating said pump, a fluid motor operated by the discharge of said pump, a rudder operated by said fluid motor, stroke adjusting meansfor varying the stroke anddirection of` discharge of said pump, an yauxiliary source of fluid pressure, means operated by said auxiliary source of fluid pressure for actuating said stroke adjusting means to different positions of adjustment, a' pair of fluid motors adapted to actuate -said stroke adjusting means to neutral position, a valve for controlling the operation of said pairof fluid motors, means connecting one end -of said valve to the pressure in said system, means connecting the other end of said valve tovsaid auxiliary source of pressure whereby when the pressure in the system imposed on said valve exceeds that imposed upon said valve by said auxiliary sourcel of pressure, said valve is actuated to establish communication between one endof said pair of fluid motors and said system pressure whereby said stroke adjusting means are actuated to neutral position, and means connecting the other ends of said pair of fluid motors to said auxiliary source of pressure whereby said motors are normally retained in ineffective position.

6. In a fluid system, the combination with a reversible discharge pump, of power means for operating said pump, a fluid motor operated by the discharge of said pump, a rudder operated by said fluid motor, strokeadjusting means for varying thel stroke and direction of discharge of said pump, an auxiliary source of fluid pressure, means operated by said auxiliary source of fluid pressure vfor actuating said stroke adjusting means to dierent positions of adjustment, a pair of fluid motors adapted to actuate s'aid stroke adjusting means to neutral position, a valve 'for controlling-the operation of saidpair of uid mo.-

tors, means connecting one end of said valve to the pressure in said system, means connecting the other end of said valve to said auxiliary source of pressure whereby when the pressure in the system A imposed upon said valve exceeds that imposed up-,l

on said valve by said auxiliary source of pressure, said valve is actuated to establish communica- Ation between one end of said pair of fluid motors and said system pressure whereby said stroke .l adjusting means are actuated to neutral position, means connecting the other ends of said pair of fluid motors to said auxiliary source of pressure whereby said motors are normally retained in ineffective position, and adjustable means for varying the pressure delivered by said v auxiliary source of fluid pressure.

ROBERT C. LAMoND. 

